Gaza Strip: Israel's military pounded targets in the Gaza Strip on Tuesday after Prime Minister Benjamin Netanyahu said his country should prepare for a long conflict in the Palestinian enclave, squashing any hopes of a swift end to 22 days of fighting.

An Israeli military spokeswoman said 70 targets were struck in Gaza through the night. At least 30 people were killed in the assaults from air, land and sea, residents said, after a night of the most widespread attacks so far in the coastal enclave.

"My house is not dearer than any of the houses of our people," Haniyeh was quoted as saying on a Hamas website. "The destruction of stones will not break our will and we will continue our resistance until we gain freedom."

The Israeli military said five soldiers were killed in a battle with militants who crossed into Israel via a tunnel near the community of Nahal Oz, close to the Gaza border.

Israeli Army Radio said Hamas gunmen fired a rocket-propelled grenade at the soldiers who were in a watchtower and then tried to drag one of the soldiers' bodies into the tunnel back to Gaza, but failed when troops fired at them, killing one militant.

Hamas said nine of its fighters carried out the attack.

"They attacked a fortified military watch tower of Nahal Oz where there were a great number of occupation soldiers," the group's armed wing, said in a statement.

The incident on Monday raised to 10 the number of military fatalities for the day.

Hamas said its broadcast outlets Al Aqsa TV and Al Aqsa Radio were also targeted. The television station continued to broadcast but the radio station went silent.

Residents said that 20 houses were destroyed during the night and two mosques were hit.

Witnesses said the fuel storage at Gaza's main power plant was struck, sending thick black plumes of smoke up into the air and leaving Gaza City and many other areas in the battered enclave without electricity.

Israel launched its offensive on July 8 saying it wanted to halt rocket attacks by Hamas and its allies. It later ordered a land invasion to find and destroy the warren of Hamas tunnels that criss-crosses the border area.

It says some of the tunnels reach into Israel and are meant for perpetrating surprise attacks on residents of nearby towns, while other underground passages in Gaza serve as Hamas bunkers and weapons caches.

More than 1,100 Gazans, most of them civilians, have been killed in the conflict. On the Israeli side, 53 soldiers have been killed as well as three civilians.

In a televised address on Monday night, a grim-faced Netanyahu said any solution to the crisis would require the demilitarisation of the Palestinian territory, controlled by Hamas and their militant allies.

"We will not finish the operation without neutralising the tunnels, which have the sole purpose of destroying our citizens, killing our children," Netanyahu said.

As night fell, army flares illuminated the sky and the sound of intense shelling was heard. The military warned thousands of Palestinians to flee their homes around Gaza City - usually the prelude to major army strikes.

"We need to be prepared for a lengthy campaign. We will continue to act with force and discretion until our mission is accomplished," Netanyahu said.

A number of rockets fired from Gaza were launched toward southern and central Israel, including the Tel Aviv area. At least one rocket was intercepted by the Iron Dome system. No casualties or damage were reported.

"His threats do not frighten either Hamas or the Palestinian people, and the (Israeli) occupation will pay the price for its massacres against children and civilians," Hamas spokesman Sami Abu Zuhri told Reuters.

International Pressure

The explosion of violence after two days of relative calm appeared to wreck international hopes of turning a brief lull into a longer-term ceasefire.

Foreign pressure has been building on Netanyahu to rein in his forces. Both US President Barack Obama and the UN Security Council called for an immediate ceasefire to allow relief to reach Gaza's 1.8 million Palestinians, followed by negotiations on a more durable end to hostilities.

But the sides are far apart. Israel wants Gaza's armed groups stripped of weapons. Hamas and its allies want the Israeli-Egyptian blockade lifted.

US Secretary of State John Kerry visited the region last week to try to stem the bloodshed, his contacts with Hamas - which Washington formally shuns - facilitated by Egypt, Turkey, Qatar and Western-backed Palestinian President Mahmoud Abbas.

Israel wants Egypt, which also borders the Gaza Strip and views Hamas as a security threat, to take the lead in curbing the Palestinian Islamists. It worries about Doha and Ankara championing Hamas demands.

Tension between Netanyahu's government and Washington has flared over US mediation efforts, adding another chapter to the prickly relations between the Israeli leader and Obama.

In New York, UN Secretary-General Ban Ki-moon deplored what he said was a lack of resolve among all parties.

"It's a matter of their political will. They have to show their humanity as leaders, both Israeli and Palestinian," he told reporters.

The main UN agency in Gaza, UNRWA, said more than 167,000 displaced Palestinians had taken shelter in its schools and buildings, following calls by Israel for civilians to evacuate whole neighbourhoods ahead of military operations.